In Afghanistan, the killings are called "green on blue" — that's when an Afghan soldier or police officer turns his gun on a NATO ally.
There was a wave of such violence just last month after U.S. soldiers accidentally burned Korans. Over the next week, six Americans were killed, apparently at the hands of Afghans working with the U.S.
The top U.S. and NATO commanders in Afghanistan think they have some answers to this recurring problem, and it's up to U.S. soldiers like Capt. Joe Fritze to see if they work.
Afghan and American officials today signed an agreement that will hand over control of the main U.S. detention center in that country to the Afghan government.
And the American commander of U.S. and international forces in Afghanistan called the agreement "another example of the progress of transition, and our efforts to ensure that Afghanistan can never again be a safe haven for terrorists."
Two more American military personnel were killed in Southern Afghanistan today when, officials believe, an Afghan civilian grabbed a weapon from an Afghan soldier and opened fire, NPR's Quil Lawrence reports from Kabul. At least one other attacker may also have been involved.
Quil adds that "we don't know yet whether this attack is linked to the Quran burnings, which set off so much violence — including the killing of four U.S. servicemen in the week that followed."